White Screen after update from 1.4 to 3.0

Hello,

My wordpress install was auto-updated recently to 4.9.15. I had a very old version of Fortuna installed, v1.4, and when WP updated, everything worked and looked fine on the front end but I would get a 500 error when trying to get into wp-admin. Through the network admin page (multisite install) I was able to update the Fortuna theme to the current 3.0, which fixed my 500 error but caused my entire site to go “white page”. I did deactivate and delete VC and Rev Slider but still no luck. Any ideas?

site is stepinsidemedia.com